Closure for large penetrations in prestressed pressure vessel - comprising flat truncated cone seated in truncated conical recess in top zone of penetration

摘要

Closure device for large penetrations in a prestressed concrete pressure vessel, esp. for nuclear power plant components, pref. comprises a lid which entirely or partly tapers upwards. The lid is held positively in place by connecting elements. The lid is positioned in a recess (22) of truncated conical sectional form in the upper zone of the penetration (13) and held in place by connecting elements between the edge (44) of the lid and the sloping wall (46) of the recess. Pref. the slope of the lid is the same of that of the recess. The dia. of the lower side of the lid is pref. smaller than the dia. of the opening. The lid is pref. held in place by clamping elements between its edge and the inner face of the opening. The lid may be additionally prestressed by prestressing cables, e.g. circumferential cables. Used for nuclear power plant components housed within the pressure vessel, e.g. heat exchangers where access for repair or replacement must be possible. The lid must also provide a seal and a radiation shield.